Reagents oxalyl chloride

Swern oxidations have been performed using the PEG2000 bound sulfoxide 34 as a dimethylsulfoxide (DMSO) substitute (reaction 13).49-50 Several alcohols were efficiently oxidized to their aldehydes or ketones using this reagent, oxalyl chloride, and triethylamine. Precipitation of the polymer with cold diethyl ether and filtration through a pad of silica afforded the desired oxidized products in very good yields and purities. The reduced sulfide polymer could be reoxidized to sulfoxide 34 with sodium metaperiodate and used again in reactions with no appreciable loss in oxidation capacity. 

Reagents Oxalyl chloride [(COCl)2]/DMF, triethylphosphite [P(OEt)3], hydrazine/THF/ben-zoic acid, uOK... 

The reaction giving A is chloromethylation, a reliable metliod of adding a CH2OH equivalent to an aromatic ring. You may have been surprised at the use of reagent B to make an acid chloride. B is oxalyl chloride and is often used when pure acid chlorides are wanted - the other products are gases (which ). 

Because of the structural requirements of the bielectrophile, fully aromatized heterocycles are usually not readily available by this procedure. The dithiocarbamate (159) reacted with oxalyl chloride to give the substituted thiazolidine-4,5-dione (160) (see Chapter 4.19), and the same reagent reacted with iV-alkylbenzamidine (161) at 100-140 °C to give the 1 -alkyl-2-phenylimidazole-4,5-dione (162) (see Chapter 4.08). Iminochlorides of oxalic acid also react with iV,iV-disubstituted thioureas in this case the 2-dialkylaminothiazolidine-2,4-dione bis-imides are obtained. Thiobenzamide generally forms linear adducts, but 2-thiazolines will form under suitable conditions (70TL3781). Phenyliminooxalic acid dichloride, prepared from oxalic acid, phosphorus pentachloride and aniline in benzene, likewise yielded thiazolidine derivatives on reaction with thioureas (71KGS471). 

The mildness of oxalyl chloride permits other sensitive hydroxyl groups ie.g., 5 -OH) to survive without protection. Even the 11 -hydroxyl group has a moderate degree of stability to this reagent. ... 

Depending on the reagent ratio, oxalyl chloride reacts with fluorobenzene m the presence of aluminum chloride to afford either 4-fluorobenzoyl chloride or 4,4 -difluorobenzophenone [ii] (equation 22). Phosgene, detected by infrared spectroscopy, is an intermediate. 

The related compounds bis(2-mothyl-3-indolyl)glyoxal (263) and bis(3-methyl-l-indolyl)glyoxai (264) - have been prepared by the action of oxalyl chloride on the Grignard reagents derived from 2-methylindole and 3-methylindole, respectively, Eis(l-methyl-3-indolyl)-glyoxal (265) was prepared by the action of oxalyl chloride on 1-methyIindole in ether. 

The early literature on the reactions of the indole Grignard reagents with the simple diacid chlorides, in particular with carbonyl chloride and oxalyl chloride (see Section III,C,4,b), is both conflicting and confusing and much of the work reported warrants repetition since the evidence presented in support of many of the structural assignments made is not entirel3 convincing. 

Vilsmeier-Haack formylation of 2-(4-methyl-l-piperazinyl)-4//-pyrido-[l,2-n]pyrimidin-4-one with a mixture of POCI3 and DMF at 95°C gave a 3-formyl derivative (93FES1225) while ethyl 4-oxo-6,7,8, 9-tetrahydro-4//-pyrido[l,2-n]pyrimidine-2-acetate at 50 °C yielded a 9-dimethylaminomethylene-3-formyl derivative (01MI4). 3-Formyl-2-hydroxy-8-[2-(4-isopropyl-l,3-thiazol-2-yl)-l-ethenyl]-4//-pyrido[l,2-n]pyri-midin-4-one was obtained from the 3-unsubstituted derivative with oxalyl chloride-DMF reagent in CH2CI2 at room temperature for 3h (OlMIPl). 

The ionic species 5, as well as 6, represent the so-called activated dimethyl sulfoxide. Variants using reagents other than oxalyl chloride for the activation of DMSO are known. In the reaction with an alcohol 1, species 5, as well as 6, leads to the formation of a sulfonium salt 7 ... 

Many procedures for the formation of carboxylic acid amides are known in the literature. The most widely practiced method employs carboxylic acid chlorides as the electrophiles which react with the amine in the presence of an acid scavenger. Despite its wide scope, this protocol suffers from several drawbacks. Most notable are the limited stability of many acid chlorides and the need for hazardous reagents for their preparation (thionyl chloride, oxalyl chloride, phosgene etc.) which release corrosive and volatile by-products. Moreover, almost any other functional group in either reaction partner needs to be protected to ensure chemoselective amide formation.2 The procedure outlined above presents a convenient and catalytic alternative to this standard protocol. 

When the substrate is oxalyl chloride (ClCOCOCl) and the reagent an unsubstituted amide, an acyl isocyanate (RCONCO) is formed. The normal product (RCONH-COCOCl) does not form, or if it does, it rapidly loses CO and HC1. ° ... 

Whereas the original Moffat-Pfitzner oxidation employs dicyclohexylcarbodiimide to convert DMSO into the reactive intermediate DMSO species 1297, which oxidizes primary or secondary alcohols via 1298 and 1299 to the carbonyl compounds and dicyclohexylurea [78-80], subsequent versions of the Moffat-Pfitzner oxidation used other reagents such as S03/pyridine [80a, 83] or oxalyl chloride [81-83] to avoid the formation of dicyclohexylurea, which is often difficult to remove. The so-called Swern oxidation, a version of the Moffat-Pfitzner oxidation employing DMSO/oxalyl chloride at -60°C in CH2CI2 and generating Me2SCl2 1277 with formation of CO/CO2, has become a standard reaction in preparative organic chemistry (Scheme 8.31). 

In absence of diluent or other effective control of reaction rate, the sulfoxide reacts violently or explosively with the following acetyl chloride, benzenesul-fonyl chloride, cyanuric chloride, phosphorus trichloride, phosphoryl chloride, tetrachlorosilane, sulfur dichloride, disulfur dichloride, sulfuryl chloride or thionyl chloride [1], These violent reactions are explained in terms of exothermic polymerisation of formaldehyde produced under a variety of conditions by interaction of the sulfoxide with reactive halides, acidic or basic reagents [2], Oxalyl chloride reacts explosively with DMSO at ambient temperature, but controllably in dichloromethane at -60°C [3]. 

Various chromogenic reagents have been used for the spectrophotometric determination of boron in seawater. These include curcumin [108,109], nile blue [110], and more recently 3,5 di-tert butylcatechol and ethyl violet [111]. Uppstroem [108] added anhydrous acetic acid (1 ml) and propionic anhydride (3 ml) to the aqueous sample (0.5 ml) containing up to 5 mg of boron per litre as H3BO3 in a polyethylene beaker. After mixing and the dropwise addition of oxalyl chloride (0.25 ml) to catalyse the removal of water, the mixture is set aside for 15-30 minutes and cooled to room temperature. Subsequently, concentrated sulfuric-anhydrous acetic acid (1 1) (3 ml) and curcumin reagent (125 mg curcumin in 100 ml anhydrous acetic acid) (3 ml) are added, and the mixed solution is set aside for at least 30 minutes. Finally 20 ml standard buffer solution (90 ml of 96% ethanol, 180 g ammonium acetate - to destroy excess of protonated curcumin - and 135 ml anhydrous acetic acid diluted to 1 litre... 

In 1965, Rauhut et al. [73] reviewed the oxalyl chloride CL system and showed that oxalyl esters could be used for this system instead of oxalyl chloride. Since then, they synthesized a number of oxalates including oxamides and established a new, potent luminescent system, namely the peroxyoxalate CL (PO CL) system. Much work has been carried out to synthesize suitable oxalic compounds. The first study dealing with different reagents was published in 1967 by Rauhut et al. [98] for the American Cyanamid Company with the purpose of developing... 

Oxidation of alcohols.1 This phosphate is apparently as efficient as oxalyl chloride for activation of DMSO for oxidation, and the derived reagent is less prone to give chlorine-containing byproducts. The reactions are rapid at 20° or below, and yields are generally 75-95%. 

A very useful group of procedures for oxidation of alcohols to ketones have been developed which involve DMSO and any one of several electrophilic reagents, such as dicyclohexylcarbodiimide, acetic anhydride, trifluoroacetic anhydride, oxalyl chloride, or... 

Oxalyl chloride (98%) was purchased from Aldrich Chemical Company, Inc., and used without further purification. Amounts of reagents for the Swern oxidation have been optimized as reported. Alternative amounts reduce both yield and % ee. 

Antibacterial activity is retained when the relatively complex amide side chains are replaced by a simple heterocycle amidine. The required reagent (7-2) is prepared by reaction of azepine formamide (7-1) with oxalyl chloride. Condensation of the product with 6-APA (2-4) leads to the formation of the amidine and thus amdinocillin (7-3) [11]. 

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